Those sharp rate hikes — averaging more than 18 percent nationally for individual policies — will be announced just before November's mid-term elections and will be an issue in many campaigns, the Democrats predict.

Democratic advocates of the ACA estimate an average 16.5 percent increase in premiums for individual policies sold in Connecticut for the next calendar year. Connecticut's health insurers have a July 16 deadline to submit rates for 2019 to the state's Insurance Department for approval.

Brad Woodhouse, campaign director at Protect Our Care and a longtime Democratic strategist, said Republicans had launched a "war on health" that will result in "eye-popping rate increases.

For the first time since the ACA became law in 2010, Democrats have adopted a national political strategy that will publicize each state's premium increases and tie those rate hikes to steps President Trump and congressional Republicans have taken to weaken the controversial health care law.

The Democratic embrace of the ACA comes after the health law has climbed, very slowly, in public support. As of last month, a key poll showed 49 percent of all Americans have a favorable view of the law, and 43 percent have an unfavorable view.

On a press call to launch the "Rate Watch" campaign, Murphy said that after Republicans failed to repeal the ACA last year, the party's goal was to "bring ruin" to Obamacare.

The GOP has taken several steps that will result in taking younger, healthier people out of insurance risk pools, raising the cost of health insurance for everyone else.

One step is to abolish the ACA's "individual mandate," which punished those who did not have health insurance with an Internal Revenue Service penalty.

Another proposal by the Trump administration, now under administrative review, is to allow insurers to sell short-term policies, whose terms are less than 364 days.

Those plans, derided as "junk" insurance by ACA proponents, would allow insurers to deny coverage to people with pre-existing health conditions and sell plans that lack coverage for maternity care, prescription drugs and other ACA-mandated benefits.

President Donald Trump also used his authority to end "cost-sharing" payments to insurers that helped them offer lower co-payments and deductibles to low-income people. The end of those subsidies led to sharp price hikes in 2018 policies.

Murphy also said the Trump administration's decision to cut the ACA enrollment period last year and stop running ads urging people to sign up for coverage was made "out of spite."

"This is a purposeful, intentional campaign of sabotage," he said.

Preliminary filings for 2019 in a few states show health insurance premiums are still going up by double digits. Democrats hope public furor at the rate hikes is targeted at the GOP.

Meanwhile, Republicans are blaming the rate hikes on what they say is the failing nature of the ACA. They say they are expanding consumer choice and offering more affordable alternatives to the burdensome Obamacare.

A number of Democratic candidates this year, however, belive support of the Affordable Care Act is a political advantage and have begun rolling out ads featuring people helped by the law.

Democrats, and a few Republicans, proposed legislation that would strengthen the Affordable Care Act, but GOP leaders did not allow votes on those bills.

"We were largely unsuccessful," Murphy said. "But we were able to stop the full repeal of the Affordable Care Act."

A number of states, including Connecticut, considered taking their own steps to shore up the ACA, including imposing a state mandate to purchase insurance.

But most of those proposals, like Connecticut's attempt to impose a state-wide mandate, faltered.

Sam Berger, a senior adviser with the liberal-leaning Center for American Progress, predicted states will renew their efforts to strengthen Obamacare after the next round of rate hikes hits and they notice that other states that were able to implement state mandates or bar "junk" plans have shielded themselves from rate shock.

"They will be looking at neighboring states who will be doing a lot better," Berger said.